The lighting industry is gradually moving towards the use of light-emitting semiconductors, such as light-emitting diodes (LEDs) due to their advantages of lower energy consumption than traditional incandescent bulbs and their lack of hazardous materials, such as mercury, which is present in compact fluorescent light bulbs (CFLs). However, in general, LEDs are positioned on a printed circuit board (PCB) that is opaque, causing light emitted from the LED to be emitted in a hemisphere generally opposite the PCB. As such, lighting devices employing PCB-based LEDs have needed to take extraordinary measures to accommodate the rigidity of traditional PCBs while still achieving desirable light distribution, namely, approximately uniform light in a 4Π steradian distribution.
Flexible circuit boards (“flex circuits”) present an alternative to traditionally rigid PCBs. Flex circuits may have a curvature along one or more axes. Additionally, flex circuits may be folded for a more abrupt change of direction beyond a minimum radius of curvature, below which the circuit folds.
Additionally, the cost of LED-based lighting devices has tended to be higher than lighting devices including other methods of emitting light due to the relatively high price of LEDs. Accordingly, fewer numbers of LEDs were economically feasible to include in a lighting device. As such, the amount of light emitted by each individual LED of a lighting device needed to be maximized, so as to produce enough light sufficient for consumer use. As the efficiency of LEDs, namely, the amount of light emitted, decreases with an increase of temperature beyond a certain threshold, an LED-based lighting device frequently employed a heat sink to increase the thermal dissipation capacity of the lighting device. A heat sink adds cost to a lighting device, as well as tending to add significant weight, as typical heat sinks are fabricated of aluminum and alloys thereof. However, as the cost of LEDs has come down, the need to operate each individual LED at a peak efficiency associated with a certain peak operating temperature is no longer necessary to maintain commercial viability, and indeed, it is becoming more economically disadvantageous to include a heat sink. However, it is still desirous to operate LEDs as close to their peak operating temperatures as is feasible. Accordingly, there is a need in the art that
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